Engine Repair Specifications (Chevrolet Tahoe 2)

General information

Engine type - V8

Working volume:

• LM7, L59 - 5.3 l
• LGM, LY5, LC9 - 5.3 l
• LQ9, LQ4, L76, LY6 — 6.0 l
• L92 — 6.2 l

Cylinder diameter:

• L59, LM7 - 96.00-96.018 mm
• L.Q4, LQ9 - 101.618-101.636 mm
• LGM, LY5, LC9 - 96.00-96.02 mm
• L76, LY6 — 101.62-101.64 mm
• L92 — 103.24-103.26 mm

Piston stroke - 92 mm

Compression ratio:

• LGM, LY5, LC9 — 9,95
• L76, LY6 — 9,67
• LQ9 — 10,1
• LQ4 — 9,41
• LM7, L59 — 9,49
• L92 — 10,5

Work order:

• in the V8 scheme - 1-8-7-2-6-5-4-3
• in the V4 scheme - 1-4-6-7

The gap between the spark plug electrodes is 1.02 mm

Cylinder block

Camshaft bearing seat diameter:

• LQ9, LQ4, LM7, L59:
• necks #1 and #5 - 59.62-59.67 mm
• necks #2 and #4 - 59.12-59.17 mm
• neck #3 - 58.62-58.67 mm
• L76, LY6, LGM, LY5, LC9, L92:
• necks #1 and #5 - 59.58-59.63 mm
• necks #2 and #4 - 59.08-59.13 mm
• neck #3 - 58.58-58.63 mm

Main bearing bed diameter - 69.87-69.89 mm

Misalignment of main bearing beds - 0.006 mm

Cylinder diameter:

• L59, LM7 - 96.00-96.018 mm
• LGM, LY5, LC9 - 96.00-96.02 mm
• LQ9, LQ4 — 101.62-101.64 mm
• L76, LY6 — 101.62-101.64 mm
• L92 — 103.24-103.26 mm

Block height (from the crankshaft axis to the mating plane of the cylinder head) — 234.57-234.82 mm

Warping of the mating surface:

• at a length of 150 mm - 0.11 mm
• by block length - 0.22 mm

Pusher guide diameter: 21.42-21.44 mm

Camshaft

Axial clearance - 0.025-0.305 mm

Shaft journal diameter: 54.99-55.04 mm

Neck ovality - 0.025 mm

Cam profile lift:

• release (without disabling cylinders):
• L59, LM7 - 6.96 mm
• LGM, LY5, LC9 - 7.20 mm
• L76 - 7.17 mm
• LQ9, LQ4, LY6 - 7.13 mm
• L92 - 7.48 mm
• release (with cylinder deactivation):
• LGM, LY5, LC9 - 7.33 mm
• L76 - 7.17 mm
• L92 - 7.61 mm
• inlet (without disabling cylinders):
• L59, LM7 - 6.82 mm
• LGM, LY5, LC9 - 7.2 mm
• L76 - 7.08 mm
• LQ9, LQ4, LY6 - 6.96 mm
• L92 - 7.48 mm
• inlet (with cylinder deactivation):
• LGM, LY5, LC9 - 7.33 mm
• L76 - 7.20 mm
• L92 - 7.61 mm

Shaft deflection (along the middle neck) — 0.05 mm

Connecting rod

Bearing clearance:

• nominal - 0.023-0.065 mm
• limit - 0.076 mm

Large head diameter: 56.51-56.53 mm

Large head ovality - 0.004-0.008 mm

Lateral clearance - 0.11-0.51 mm

Crankshaft

Connecting rod journal diameter:

• nominal - 53.32-53.34 mm
• limit - 53.31 mm

Crankpin ovality:

• nominal - 0.005 mm
• limit - 0.01 mm

Crankpin taper (1/2 the length of the neck):

• nominal - 0.005 mm
• limit - 0.02 mm

Axial clearance - 0.04-0.2 mm

Main bearing clearance:

• nominal - 0.02-0.05 mm
• limit - 0.065 mm

Main journal diameter:

• nominal - 64.99-65.01 mm
• limit - 64.99 mm

Ovality of the root neck:

• nominal - 0.003 mm
• limit - 0.008 mm

Main journal taper:

• nominal - 0.01 mm
• limit - 0.02 mm

Rear flange runout - 0.05 mm

Synchronizing ring runout (measure 1 mm below the tooth gullet diameter) — 0.7 mm

Neck width for thrust bearing:

• nominal - 26.14-26.22 mm
• limit - 26.22 mm

Surface runout under the thrust bearing - 0.025 mm

Cylinder head

Head height (from the fire bottom to the plane of the valve cover) — 120.2 mm



Valve guide installation height (measured from the spring seat) — 17, 32 mm

Warping of the mating surface:

• exhaust manifold - 0.13 mm
• intake manifold - 0.08 mm
• block
• at a length of 150 mm - 0.08 mm
• along the entire length - 0.1 mm

Intake manifold

Flange warping (over a length of 200 mm, including two inlet channel windows) — 0.3 mm

Piston and piston pin

Piston pin diameter - 23.952-23.955 mm

Piston boss clearance:

• nominal - 0.002-0.01 mm
• limit - 0.015 mm

Small End Clearance:

• nominal - 0.007-0.02 mm
• limit - 0.022 mm

Piston diameter (43 mm from the piston head):

• L59, LM7, LGM, LY5, LC9 - 96.002-96.036 mm
• LQ4 — 101.606-101.640 mm
• LQ9, L76, LY6 — 101.611-101.642 mm
• L92 — 103.23-103.26 mm

Cylinder clearance:

• LQ4:
• nominal - 0.022-0.030 mm
• limit - 0.07 mm
• LQ9:
• nominal - 0.022-0.030 mm
• limit - 0.08 mm
• L59, LM7, LGM, LY5, LC9, L92:
• nominal - 0.036-0.016 mm
• limit - 0.071 mm
• L76, LY6:
• nominal - 0.022-0.08 mm
• limit - 0.08 mm

Piston rings

Gap in the lock:

• first compression:
• LQ9, LQ4:
• nominal - 0.31-0.52 mm
• limit - 0.59 mm
• L59, LM7, LGM, LY5, LC9, L92:
• nominal - 0.23-0.44 mm
• limit - 0.5 mm
• L76, LY6:
• nominal - 0.20-0.41 mm
• limit - 0.41 mm

• second compression:
• LQ9, LQ4:
• nominal - 0.51-0.77 mm
• limit - 0.84 mm
• L59, LM7, LGM, LY5, LC9, L92:
• nominal - 0.44-0.70 mm
• limit - 0.76 mm
• L76, LY6:
• nominal - 0.37-0.69 mm
• limit - 0.69 mm

• oil scraper:
• LQ9, LQ4:
• nominal - 0.31-0.77 mm
• limit - 0.94 mm
• L59, LM7, LGM, LY5, LC9, L92:
• nominal - 0.18-0.75 mm
• limit - 0.81 mm
• L76, LY6:
• nominal - 0.22-0.79 mm
• limit - 0.79 mm

End clearance in the piston groove

• LQ9:
• first compression - 0.04-0.08 mm
• second compression - 0.04-0.08 mm
• oil scraper - 0.012-0.2 mm
• LQ4:
• first compression - 0.04-0.08 mm
• second compression - 0.04-0.08 mm
• oil scraper - 0.015-0.2 mm
• L59, LM7, LGM, LY5, LC9, L92:
• first compression - 0.04-0.085 mm
• second compression - 0.04-0.078 mm
• oil scraper - 0.012-0.2 mm
• L76, LY6:
• first compression - 0.03-0.10 mm
• second compression - 0.035-0.078 mm
• oil scraper - 0.013-0.2 mm

Valves

The angle of the valve shut-off chamfer is 45°

Seat locking chamfer angle - 46°

The width of the locking chamfer is 1.25 mm

Drive clearance - no, hydraulic tappet

Valve lift:

• release (without disabling cylinders):
• L59, LM7 - 11.85 mm
• LQ9, LQ4 - 12.16 mm
• LGM, LY5, LC9 - 12.24 mm
• L76 - 12.19 mm
• LY6 - 12.12 mm
• L92 - 12.72 mm
• release (with cylinder deactivation):
• LGM, LY5, LC9 - 12.46 mm
• L76 - 12.41 mm
• L92 - 12.94 mm
• inlet (without disabling cylinders):
• L59, LM7 - 11.60 mm
• LQ9, LQ4 - 11.79 mm
• LGM, LY5, LC9 - 12.24 mm
• L76 - 12.04 mm
• LY6 - 11.83 mm
• L92 - 12.72 mm
• inlet (with cylinder deactivation):
• LGM, LY5, LC9 - 12.46 mm
• L76 - 12.24 mm
• L92 - 12.94 mm

Misalignment of valve seat and guide - 0.05 mm

Seat locking chamfer width:

• release - 1.78 mm
• inlet - 1.02 mm

Valve stem diameter:

• nominal - 7.955-7.976 mm
• limit - 7.95 mm

Gap in the guide (inlet and outlet):

• nominal - 0.025-0.066 mm
• limit - 0.093 mm

Rocker arm gear ratio - 1.70

Valve spring length:

• in a free state - 52.9 mm
• installation - 45.75 mm

Spring compression force:

• up to length 45.75 mm - 340 N
• up to length 33.55 mm - 980 N

Lubrication system

Filling capacity:

• with filter - 5.7 l
• without filter - 5.2 l

Oil pressure (the engine is warmed up):

• at 1000 rpm - 41 kPa
• at 2000 rpm - 124 kPa
• at 4000 rpm - 165 kPa

Opening pressure of the pressure reducing valve of the cylinder deactivation system - 379-517 kPa

Oil pan

Front and rear cover clearance (measure from the plane of the pallet) — 0.0-0.5 mm

Deviation from the flywheel housing mounting surface is 0.0-0.1 mm

[The article is reprinted from the website: CHEVYMAN.ru]